Packaging material folding device of packaging machine

ABSTRACT

A wrapper folding apparatus of a packaging machine has a second wheel ( 10 ) for use as a folding turret. The second wheel ( 10 ) is supplied with a cigarette bundle and an aluminized sheet (S) in an inlet position. As this is done, the aluminized sheet (S) is folded around the periphery of the cigarette bundle, and lug portions formed by the peripheral folding are folded by the use of primary lug folding guides ( 36 ). Since the lug protions are kept folded by the use of holding guides ( 38 ) thereafter, they cannot be freed until an outlet position is reached. When the cigarette bundle is discharged in the outlet position of the second wheel ( 10 ), the lug portions on the end-flap side are folded by the use of secondary lug folding guides ( 46 ). After the folding, side flaps continue to be folded without allowing the lug portions to be free.

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/JP01/07911 which has an Internationalfiling date of Sep. 12, 2001, which designated the United States ofAmerica.

TECHNICAL FIELD

The present invention relates to a wrapper folding apparatus for foldinga wrapper around a product in a fold-packaging machine.

BACKGROUND ART

Articles such as cigarettes and filter cigarettes are packaged in abundle based on a given number. Conventionally, this packet includesinside packaging for maintaining the flavor quality of cigarettes andoutside packaging for externally indicating the cigarette brand and thelike. A cigarette packet, having undergone the inside packaging andoutside packaging, is further externally wrapped in a covering film. Amaterial that is formed of paper laminated with metal foil, such as tinfoil or aluminum foil, having high quality maintaining function can besuitably used as the inner wrapper in which a cigarette bundle is to bewrapped. The material having the metal foil is so flexible that it canbe folded with ease. After the material is folded, the material cannaturally maintain its folded state.

Conventionally, therefore, a cigarette packaging machine uses a step offolding the inner wrapper, the step utilizing the properties of metalfoil. After the inner wrapper is wound around the periphery of acigarette bundle, in the cigarette packaging machine, movable foldingclaws are caused to advance into to-be-folded regions, which projectsideways in the form of the square tube of the inner wrapper, accordingto predetermined steps of folding procedure. As this is done, theregions of the inner wrapper are folded. After one step of foldingprocedure is finished, the folding claws are quickly retracted to beready for the next folding cycle. When the cigarette bundle is in theform of tiers of bales, for example, the to-be-folded regions of theinner wrapper that are located at opposite sides in the width directionof the cigarette bundle are referred to as lug portions. When each ofthe lug portions are folded, a pair of side flaps that are opposite toeach other in the thickness direction of the cigarette bundle areformed, respectively. As this is done, the folding claws for folding thelug portions laterally advance toward the cigarette bundle, fold the lugportions along the end faces (aggregation of cigarette end faces orfilter end faces) of the cigarette bundle, and then quickly retract fromthe end faces. When the aforesaid side flaps are folded in succession,thereafter, the inside packaging of the cigarette bundle is completed.

In the folding step described above, however, the lug portions are freedduring the time interval that elapses from the instant that the lugportions of the inner wrapper are folded until the side flaps arefolded, because of the retracting of the folding claws. In some cases,therefore, the lug portions are then apt to return to the state beforethe folding operation. If the extent of this return is extremely large,the side flaps that are once formed also get out of shape. Thereafter,neither the side flaps nor the lug poritons can be regularly folded,thus resulting in failure in inner wrapper folding.

Recently, moreover, recyclable materials have started to be used aspackaging materials for cigarettes in consideration of environmentalload. That is, there are increasing opportunities of usinghigh-elasticity materials, such as deposited metal film, in place ofconventional high-plasticity materials based on metal foil. If thedeposited metal film, which is poor in plasticity, is used as an innerwrapper, in particular, the deposited metal film itself can hardly beexpected naturally to maintain its folded state in the aforesaid foldingprocess. If the deposited metal film is used as the inner wrapper,therefore, the inner wrapper folding operation in the cigarettepackaging machine is liable to become more unstable.

In some cases, on the other hand, the wrapper folding operation maybecome unstable due to mechanical factors of the packaging machine, aswell as to the characteristic factors of the packaging material. Thefold wrapping of a product as well as the cigarette bundle comprises,for example, a step of folding a wrapper around a product and thenfolding end-flaps of the wrapper on the product, a step of folding lugportions of the wrapper that are caused to project sideways from theproduct, thereby forming a pair of side flaps at each side, and a stepof successively folding the pair of side flaps.

According to a folding manner that is frequently used in the step ofside flap folding, among other manners, the product is transported alongfolding lines of the side flaps, for example, and the side flaps areguided in being folded along folding guides in this process oftransportation. Each folding guide has a guide surface that guides aside face of the product, and a folding edge is formed on the extremeend of the guide surface. The folding edge extends diagonally across thepath of transportation of the product. As the product is transported,the side flap is guided by the folding edge and folded onto the sideface of the product. If the product is transported sideways, forexample, the pair of side flaps, upper and lower, are formed beside theproduct as the lug portions of the wrapper are folded. When the upperside flap is guided in being folded by means of the folding guide,thereafter, a difference in level corresponding to the length ofprojection of the upper side flap is secured between the starting andterminal ends of the folding edge. The starting end is located slightlyabove the upper side flap. As the product is transported, therefore, theupper side flap engages the folding edge and is folded down along thefolding edge during its passage. When the upper side flap passes theterminal end of the folding edge, the upper side flap is held betweenthe product and the guide surface, whereupon folding the upper side flapis finished.

According to the folding method described above, the lateral force oftransportation is supposed to be converted into a downward force ofdepression when the upper side flap of the wrapper is slid relatively tothe folding edge as the product is transported. This force of depressioncan cause the upper side flap to be laid over the sided face of theproduct so that the upper side flap can be brought gradually intointimate contact with the side face of the product, its proximal endportion first.

If the coefficient of friction between the wrapper and the folding edgeis extremely high, for example, however, the folding edge is subjectedto an excessive resistance opposite to the direction of movement of thewrapper, so that the side flap is then dragged heavily. If the wrapperlacks in rigidity depending on its material, the force received from thefolding edge may be concentrated only on a part of the side flap andfail to be effectively transmitted as a force to bend the side flap insome cases. In these circumstances, it is hard to fold the side flapaccurately along its regular crease.

With the recent improvement of the production capacity of cigarettemanufacturing machines, moreover, the cigarette packaging machine, forexample, has started to require shorter packaging cycles. Thus, a stepof wrapping a cigarette bundle in an inner wrapper, for example,requires development of technique for folding side flaps whiletransporting the cigarette bundle at a higher speed in a shorterinterval of transportation.

DISCLOSURE OF THE INVENTION

The object of the present invention is to provide a wrapper foldingapparatus of a packaging machine, capable of accurately folding awrapper with stability without regard to its material in fold wrappingof various packaged products including cigarette bundles.

A wrapper folding apparatus of a packaging machine according to thepresent invention is realized by the use of a wrapper folding turret.The folding turret has an inlet position and an outlet position for acigarette bundle to be wrapped. A pocket is supplied with the cigarettebundle and an inner wrapper in the inlet position. During this supply,the inner wrapper is folded around the periphery of the cigarettebundle. The pocket of the folding turret is provided with first lugfolding guides. The lug folding guides folds one-sided lug portions ofthe inner wrapper, which are formed by the peripheral folding of theinner wrapper, as the inner wrapper is peripherally folded, andmaintains the folded state of the one-sided lug portion until the outletposition is reached.

On the other hand, end flaps of the inner wrapper are folded between theinlet and outlet positions of the folding turret, whereupon theother-sided lug portions paired with the one-sided lug portions,respectively are formed. The folded state of the end flaps is maintaineduntil the outlet position is reached. When the cigarette bundle ispartially wrapped in the inner wrapper as the end flaps are folded, theresulting semifinished inner pack is discharged from the pocket in theoutlet position of the folding turret.

Second lug folding guides for folding the other-sided lug portions asthe semifinished inner pack is discharged are located in the outletposition of the folding turret. As the other-sided lug portions arefolded in this manner, a pair of side flaps are formed with both theone-sided and the other-sided lug portions between them, respectively.

Side flap folding guides are located immediately on the lower-streamside of the second lug folding guides as viewed in the direction ofdischarge of the semifinished inner pack. The guides fold one of thecorresponding pair of side flaps after the other-sided lug portions arefolded.

A transportation turret is located close to the folding turret. Thesemifinished inner pack discharged from the pocket of the folding turretis then pushed into a pocket of the transportation turret. The pocket ofthe transportation turret is provided with folding edges. As thesemifinished inner pack is pushed in, the folding edges fold the otherside flaps respectively.

When the one-sided lug portions are folded as the inner wrapper isperipherally folded, according to the inner wrapper folding apparatusdescribed above, the one-sided lug portions are kept folded by means ofthe first lug folding guides until one of the side flaps is folded. Whenthe other-sided lug portions are folded, the one side flap is foldedwithout delay, so that neither of the one-sided and the other-sided lugportions can be freed after they are folded.

Thus, the wrapper folding apparatus of the packaging machine of thepresent invention can always steadily fold the wrapper without regard tothe quality of the material that is used as the inner wrapper for thecigarette bundle. Since the inner pack is formed in an accurately foldedconfiguration, moreover, a satisfactory quality can be secured for acigarette pack to be completed afterward.

Preferably, each of the first lug folding guides may include astationary guide and a holding guide. The stationary guide is fixed inthe inlet position of the folding turret. As the folding turret rotates,on the other hand, the holding guide can move together with the pocket.Further, the stationary guide guides the one-sided lug portion in beingfolded as the inner wrapper is peripherally folded. As this is done, theholding guide adjoins the stationary guide in the inlet position. Whenthe cigarette bundle is fed into the pocket, the outer surface of thecigarette bundle can be held by means of the one-sided lug portion thatis folded. If the stationary guide and the holding guide are thus formedseparately, an existing packaging machine can be modified with ease.

Although the wrapper folding apparatus described above is suited for theinside packaging of the cigarette bundle, there may alternatively beprovided the following wrapper folding apparatus that is suited for theinside packaging or external wrapping of various products.

More specifically, the wrapper folding apparatus of a packaging machineof the present embodiment comprises lug folding means, transportationmeans, and side flap folding guides. The lug folding means folds regionspaired in the width direction of a product, out of to-be-folded portionsof a wrapper that are formed by subjecting the wrapper to peripheralfolding and end-flap folding around the product, thereby forming a pairof side flaps on the wrapper respectively. The transportation meanstransports the product along a folding line of the side flap with theside flaps formed in this manner. The side flap folding guides guide theone side flap in being folded as the product is transported. Each of theside flap folding guides has a curved guide surface. The curved guidesurface comes into surface contact with the one side flap to be foldedduring the passage of the side flap, so that the side flap is subjectedto a folding surface pressure in the direction of rolling around thefolding line in the surface contact area.

According to the wrapper folding apparatus provided with the side flapfolding guides described above, a force in the direction oftransportation is converted into a folding surface pressure when theside flap slides with respect to the curved guide surface as the productis transported. The folding surface pressure converts linear movement ofthe side flap into circular motion around the folding line, so that theentire surface contact area of the curved guide surface can efficientlyguide the side flap in being folded.

Thus, the wrapper folding apparatus of the present invention can realizeefficient side flap folding for various wrappers and complete stableaccurate fold wrapping. Since it is never influenced by the coefficientof friction between the wrapper and the guide or the rigidity of thewrapper, a packaging machine with high versatility can be provided.

The curved guide surface is realized including a curved surface that isobtained by a geometrical method, and this curved surface is defined bya trace of a given straight line. More specifically, the curved surfaceis defined by a trace that is formed when a straight line, extending atan acute angle to the folding line within a plane along the one sideflap not folded yet and on the upper-stream side as viewed in thedirection of transportation of the product from the folding line, isrotated around the folding line in the folding direction of the one sideflap as the straight line is moved in the direction of transportation.Preferably, the straight line is rotated for an angle at which the sideflap is to be folded.

The trace of the straight line described above forms a fixed slope withrespect to the folding line in an arbitrary infinitesimal portion aroundthe folding line. This slope is composed of an angle between thestraight line and the folding line, a moving speed component of thestraight line in the direction of transportation of the product, and arotational speed component around the folding line. Since the straightline has a downward gradient toward the folding line as viewed in thedirection of transportation of the product, the aforesaid slope canconvert the force in the direction of transportation of the productalong the inclination of the straight line, thereby subjecting the sideflap to a centripetal force toward the folding line.

Preferably, the angle formed between the straight line and the foldingline is set within the range of 10° to 80°. The magnitude of centripetalforce varies depending on this angle.

If the shape of the curved guide surface is defined geometrically, theshape can be easily changed according to various conditions, such as thespeed of product transportation, wrapper folding travel, folding angle,etc.

Each of the side flap folding guides further has friction reducing meansfor lowering the coefficient of friction between the curved guidesurface and the wrapper. In this case, the guide can be applied tofolding of a wrapper with an extremely high coefficient of friction withthe curved guide surface, and can more easily meet conditions related tothe type of the wrapper, speed of product transportation, foldingtravel, folding angle, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a hinge-lidded package for filtercigarettes;

FIG. 2 is a schematic view of a packaging machine for manufacturing thehinge-lidded package of FIG. 1;

FIG. 3 is a perspective view specifically showing a configuration of afolding section of the packaging machine of FIG. 2;

FIG. 4 is a perspective view for illustrating steps of operation in thefolding section of the packaging machine of FIG. 2;

FIG. 5 is a side view specifically showing a folding guide set;

FIG. 6 is a perspective view specifically showing a configuration ofside flap folding guides;

FIG. 7 is a perspective view for geometrically illustrating the shape ofa curved guide surface;

FIG. 8 is a perspective view showing an infinitesimal slope thatconstitutes part of the curved guide surface; and

FIG. 9 is a partial sectional view showing equipment for reducingfriction between the curved guide surface and a wrapper.

BEST MODE FOR CARRYING OUT THE INVENTION

As shown in FIG. 1, filter cigarettes are packaged in a hinge-liddedpackage P in the form of a box, for example. The hinge-lidded package Pfor use as an outer package for the filter cigarettes comprises anopen-topped pack body B. The pack body B can store an inner pack offilter cigarettes therein. A lid L is coupled to the rear wall (notshown) of the pack body B by means of a self-hinge. The top opening ofthe pack body B can be opened or closed by rotating the lid L around theself-hinge. Further, a front opening edge of the pack body B is formedby an inner frame F. When the lid L is shut down, the lid L is put onthe inner frame F. The pack body B is stored with, for example, twentyfilter cigarettes in a bundle. This bundle of filter cigarettes iswrapped in an inner wrapper and forms the inner pack IB. When the lid Lis lifted opened as illustrated, the inner pack IB is partially exposed.

The package of FIG. 1 is manufactured by means of a packaging machineshown in FIG. 2, for example. The pack body B and the lid L of thehinge-lidded package P can be formed from one blank BL1. Further, theinner frame F is formed from a dedicated blank BL2. The blank BL2 andthe blank BL1 are supplied to a packaging line via separate paths. InFIG. 1, a wrapper folding apparatus of the present invention is locatedin a folding section for the inner wrapper. First, the generalconfiguration of the packaging machine will be described in brief.

The packaging machine is provided with a hopper 2 for filter cigarettes.The filter cigarettes having undergone a quality inspection arecontinuously supplied from a filter attachment (not shown) into thehopper 2. A pocket conveyor 5 having a large number of mouthpieces 4 islocated near the hopper 2. The pocket conveyor 5 extends from the hopper2 toward the inner wrapper folding section. A cigarette fillingmechanism 6 is provided under the hopper 2. The filling mechanism 6thrusts out the twenty filter cigarettes in three tiers of bales throughthe outlet of the hopper 2. The thrust filter cigarettes are filled intoeach mouthpiece 4, whereupon they form a cigarette bundle. The cigarettebundle, along with the mouthpiece 4, is transported and fed toward theaforesaid folding section.

That part of the packaging line of the packaging machine which extendsbeyond the pocket conveyor 5 is defined by a large number of wheel trainindicated by dashed lines in FIG. 1. The mouthpiece 4 is transported toa vertical first wheel 8, and the first wheel 8 receives the cigarettebundle from the mouthpiece 4. As it rotates intermittently, the firstwheel 8 transports the received cigarette bundle toward a subsequentvertical second wheel 10.

The second wheel 10 is formed of a folding turret for aluminized sheetsS. The second wheel 10 includes a plurality of pockets 12 that arearranged at equal spaces in the circumferential direction of the wheel10. The second wheel 10 centers the aforesaid inner wrapper foldingsection.

The aluminized sheets S are obtained by cutting an aluminized film webAW that is delivered from a web roll AR into given lengths, and aresuccessively fed to the region between the first wheel 8 and the secondwheel 10 by means of a suction conveyor (not shown). Another web roll(not shown) of the same specifications is located near the web roll AR,and this web roll is currently on standby. If the remainder of theworking web roll AR becomes insufficient, thereafter, a new aluminizedfilm web is drawn out from the roll on standby and automaticallyconnected to the working aluminized film web AW.

A horizontal third wheel 16 adjoins the second wheel 10 on the sideopposite from the first wheel 8. The third wheel 16 successivelyreceives cigarette bundles from the second wheel 10 into one of pocketsthereof. As the wheel 16 rotates intermittently, the wheel 16 transportsthe inner pack IB of each cigarette bundle.

Further, a fourth wheel 18, also horizontal, adjoins the second wheel 16on the side opposite from the second wheel 10. The fourth wheel 18 issituated below the third wheel 16, and pockets of the wheel 18successively overlap the pocket of the third wheel 16 as the wheels 16and 18 rotate intermittently.

As the fourth wheel 18 rotates intermittently, the wheel 18 is suppliedwith the aforesaid blanks BL2 from one blank supply path 20, andtransports inner frames, which are formed by folding the blanks BL2toward the third wheel 16.

When the pocket of the fourth wheel 18 and the pocket of the third wheel16 vertically overlap one another, the aforesaid inner pack IB in thepocket of the third wheel 16 are pushed individually into the pocket ofthe fourth wheel 18. In these pockets, the inner pack IB is combinedwith the inner frame and bonded together. Thereafter, the inner pack IBwith the inner frame is transported as the fourth wheel 18 rotatesintermittently.

On the other hand, the fourth wheel 18 is supplied with the aforesaidblanks BL1 from the other blank supply path 22, and the blank BL1 isbonded individually to the upper surface of the inner pack IB with theinner frame between them. As seen from FIG. 2, the blank supply path 22connects a hopper 24 and the fourth wheel 18. The blanks BL1 that aretaken out one after another from the hopper 24 are transported along thepath 22 toward the fourth wheel 18.

A vertical fifth wheel 25 is located right over the position of supplyof each blank BL1 as viewed in the circumferential direction of thefourth wheel 18. The fifth wheel 25 receives the inner pack IB, havingthe blank BL1 bonded thereto, into one of pockets thereof. As this isdone, the inside wall portions of the blank BL1 are foldedsimultaneously on the inner pack. As the fifth wheel 25 then rotatesintermittently, the blank BL1 is further folded in succession, whereupona hinge-lidded package P is completed.

Thereafter, the hinge-lidded package P is transferred to a horizontalseventh wheel 28 via a horizontal sixth wheel 26 that adjoins the fifthwheel 25. As the seventh wheel 28 rotates intermittently, the wheel 28transports the hinge-lidded package P. In this process oftransportation, glued portions of the blanks BL1 and BL2 are dried.Thereafter, the hinge-lidded package P is delivered through a verticaleighth wheel 30 to a package delivery line 32. The package delivery line32 successively feeds the hinge-lidded packages P toward a film-wrappingmachine (not shown), and the film-wrapping machine wraps eachhinge-lidded package P in a film sheet.

FIG. 3 specifically shows the inner wrapper folding section of thepackaging machine. The second wheel 10 or the folding turret centers theinner wrapper folding section.

The inlet position of the folding turret is located between the secondwheel 10 and the first wheel 8. In this inlet position, the empty pocket12 of the second wheel 10 is supplied with the cigarette bundle and thealuminized sheet S. The cigarette bundle is pushed out from the firstwheel 8 by means of a pusher 34, and is plunged into the pocket 12 ofthe second wheel 10 in the inlet position. As this is done, thealuminized sheet S is folded in the shape of a U along the periphery ofthe cigarette bundle and, along with the cigarette bundle, is receivedin the pocket 12.

Primary lug folding guides 36 are fixed in the inlet position of thesecond wheel 10. The primary lug folding guides 36 are located justshort of the pocket 12 as viewed in the plunging direction of thecigarette bundle on the opposite sides of the pocket 12, respectively.On the other hand, each individual pocket 12 of the second wheel 10 isprovided with a pair of holding guides 38 that extend along the oppositesides of the pocket 12. These holding guides 38 are ranged in theplunging direction of the cigarette bundle with respect to the primarylug folding guides 36 in the aforesaid inlet position, respectively.

When the aluminized sheet S is folded in the aforesaid manner, primarylug portions are formed individually on the opposite sides of thecigarette bundle. At the same time, the primary lug folding guides 36guide the primary lug portions in being folded along the opposite endfaces of the cigarette bundle. The primary lug portions that are foldedin this manner are located inside the second wheel 10 as viewed in itsdiametrical direction thereof. When end flaps of the sheet S are foldedthereafter, secondary lug portions are formed outside the second wheel10 as viewed in its diametrical direction thereof. The primary andsecondary lug portions should be formed in pairs beside the cigarettebundle.

As the cigarette bundle is plunged further, the primary lug portionsthat are folded by means of the primary lug folding guides 36 are heldbetween the holding guides 38 and the cigarette bundle. Thereafter, theholding guides 38 can hold the opposite end faces of the cigarettebundle with the primary lug portions of the aluminized sheet S betweenthem. Only one of the primary lug folding guides 36 of each pocket 12and one of the holding guides 38 are shown in FIG. 3, and the otherprimary lug folding guide 36 and the other holding guide 38 are not.

When the cigarette bundle is fully plunged into the pocket 12, thepusher 34 retracts from the second wheel 10, and the second wheel 10rotates intermittently in the clockwise direction of FIG. 3. As thesecond wheel 10 rotates intermittently, moreover, another empty pocket12 moves to the inlet position.

A movable end-flap folding guide 40 and a stationary guide plate 42 areprovided outside the second wheel 10. The end-flap folding guide 40rotates toward the outer peripheral surface of the second wheel 10,thereby folding one of the end flaps along the periphery of thecigarette bundle. When the second wheel 10 then rotates, the other endflap is guided and folded by means of the guide plate 42, whereuponfolding the end flaps of the aluminized sheet S is completed. The innerperipheral surface of the guide plate 42 extends along the outerperiphery of the second wheel 10 toward the outlet position. The guideplate 42 serves to keep the end flaps folded. When the end flaps of thealuminized sheet S are folded, as mentioned before, the secondary lugportions are formed individually on the opposite sides of the cigarettebundle and are located outside second wheel 10 as viewed in itsdiametrical direction thereof. The way of folding the secondary lugportions will be mentioned later.

The primary lug portions that are already folded are kept in its foldedstate by means of the holding guides 38. The holding guides 38 canmaintain the folded state of the primary lug portions as the secondwheel 10 rotates from the inlet position to the outlet position.

The outlet position of the second wheel 10 is opposite to the inletposition with respect to its center of rotation. A discharge pusher 44is located in the outlet position. In this outlet position, the pusher44 pushes out the cigarette bundle together with the aluminized sheet Sfrom the pocket 12. As this is done, the cigarette bundle is partiallywrapped in the sheet S. When the cigarette bundle is discharged from thepocket 12, therefore, it is in the form of a semifinished inner pack.

Further, secondary lug folding guides 46 for use as second lug foldingguides are provided in the outlet position of the second wheel 10. Thesesecondary guides 46 are also located on the opposite sides of the pocket12, respectively. The secondary lug folding guides 46 are positionedjust ahead of the pocket 12 as viewed in the direction of discharged ofthe semifinished inner pack. Side flap folding guides 48 are arrangedimmediately on the lower-stream side of the secondary lug folding guides46, individually. Only one of the secondary lug folding guides 46 andone of the side flap folding guides 48 are shown in FIG. 3.

When the discharge pusher 44 discharges the semifinished inner pack fromthe pocket 12 of the second wheel 10, the secondary lug folding guides46 guide the secondary lugs on the end-flap side in being folded. As thesecondary lug portions are folded, moreover, a pair of side flaps, upperand lower, are formed individually on the opposite sides of thecigarette bundle, respectively. After the secondary lug portions arefolded, the side flap folding guides 48 fold the upper side flap and putit on the primary and secondary lug portions that are already folded.

When the discharge of the semifinished inner pack is completed, thefolded upper side flap and both the lug portions are sandwiched betweenthe side flap folding guides 48 and the side faces of the cigarettebundle. The side flap folding guides 48 can cause the upper side flapand the lug portions to hold the side faces of the cigarette bundle,thereby maintaining the folded state. The lower side flap that is notfolded yet is situated right under the side flap folding guides 48 andprojects sideways from the cigarette bundle.

When the discharge of the semifinished inner pack from the pocket 12 ofthe second wheel 10 is completed as described above, the pack is locatedupwardly a pocket 52 of the third wheel 16 so as to be superposed on thepocket 52. In this position, moreover, a stuffing pusher 50 is locatedover the pocket 52. The pusher 50 can push the discharged semifinishedinner pack into the pocket 52 of the third wheel 16.

The pocket 52 is formed of a rectangular frame, which has a shape suchthat the pocket 52 can receive the cigarette bundle only in the form ofa completed inner pack. When the cigarette bundle in the form of thesemifinished inner pack is pushed into the pocket 52, therefore, thelower side flap is guided in being folded by means of the upper edge ofthe inner peripheral wall of the pocket 52. When the cigarette bundle isfully pushed into the pocket 52, folding the lower side flap isfinished, whereupon the inner pack IB of the cigarette bundle iscompleted.

As the aluminized sheet S is folded in the folding section of thepackaging machine in the aforesaid manner, none of the lug portions ofthe aluminized sheet S are free in the middle of the operation. Thematerial of the inner wrapper is not limited to aluminized film, and mayalternatively be paper laminated with metal foil, such as aluminum foil.

Although the primary lug folding guides 36 and the holding guides 38 inthe inlet position of the second wheel 10 are formed separatelyaccording to the embodiment described above, they may be formedintegrally with one another. In this case, each pocket 12 is providedwith members, each of the members integrally including a lug foldingguide and a holding guide for the aluminized sheet S.

The wrapper folding apparatus of the present invention may be suitablymodified to match the form of the cigarette packaging machine to whichthe apparatus is installed. More specifically, the wrapper foldingapparatus of the invention is intended to keep the folded state of thelug portions formed by folding the inner wrapper (aluminized sheet oraluminum foil sheet) until the pair of side flaps formed by the foldingare lapped on the lug portions. Thus, specific means for fulfilling theaforesaid function is not limited to the form described above.

The side flap folding guides of the wrapper folding apparatus of thepresent invention will now be described in detail. The wrapper foldingapparatus with the side flap folding guides described below isapplicable to packaging machines for various products, as well as to thecigarette packaging machine. For ease of illustration, however, thewrapper folding apparatus is supposed to be applied to the cigarettepackaging machine shown in FIG. 1 in the description to follow.

FIG. 4, like FIG. 3, shows the inner wrapper folding section. However,the pusher 34, holding guides 38, end-flap folding guide 40, stationaryguide plate 42, etc. shown in FIG. 3 is not shown in FIG. 4. In FIG. 4,moreover, the secondary lug folding guide 46 and the side flap foldingguide 48 are represented by one folding guide set 54. The cigarettebundle in the second wheel 10 is internally wrapped according to thesame steps as aforementioned.

FIG. 5 specifically shows the folding guide set 54. As shown in thisdrawing, the folding guide set 54 includes the secondary lug foldingguide 46 and the side flap folding guide 48. The secondary lug foldingguide 46 is located on the upper-stream side of the cigarette bundle asviewed in the discharge direction of the cigarette bundle, and the sideflap folding guide 48 is located immediately on the lower-stream side ofthe secondary lug folding guide 46 so as to adjoin it. Only one foldingguide set 54 is shown FIG. 5.

When the cigarette bundle is discharged horizontally along the foldingguide set 54 by the agency of the aforesaid discharge pusher 44, thesecondary lug folding guide 46 first guides a region of the folded endflaps of the aluminized sheet S, that is, a secondary lug portion, inbeing folded. This region is only tucked in the direction opposite tothe discharge direction of the cigarette bundle, so that the foldingoperation thereof can be completed when a relatively short distance (lugfolding travel in FIG. 5) is covered. This folding operation forms apair of side flaps, upper and lower, on each of the opposite sides ofthe cigarette bundle. All the upper and lower side flaps (not shown inFIG. 5) extend horizontally and sideways from the cigarette bundlebefore they are folded.

As the cigarette bundle is further discharged, the cigarette bundle ismoved in the side flap folding travel shown in FIG. 5. As this is done,the side flap folding guides 48 guide upper side flaps SF1, out of theupper and lower side flaps, in being folded.

FIG. 6 specifically shows the side flap folding guides 48 describedabove. Each side flap folding guide 48 is formed having a curved guidesurface 56 that is hatched in the drawing. Further, a raked plate 58 isformed on one end of each side flap folding guide 48 on the upper-streamside as viewed in the discharge direction of the cigarette bundle. Thisraked plate 58 is continuous with the starting end of the curved guidesurface 56, and extends horizontally toward the upper-stream side in thedischarge direction the cigarette bundle. The opposite side flap foldingguides 48 form a symmetrical configuration, and individually havevertical guide surfaces 60 facing to each other. Each vertical guidesurface 60 extends in the discharge direction of the cigarette bundlefrom the terminal end of the aforesaid curved guide surface 56.

When the cigarette bundle in the form of the semifinished inner pack ismoved between the opposite side flap folding guides 48, the respectiveraked plates 58 of the side flap folding guides 48 are situated slightlyabove the upper side flaps SF1. As the semifinished inner pack is moved,therefore, the upper side flaps SF1 are guided along the respectivelower surfaces of the raked plates 58 and then led to the curved guidesurfaces 56. When the semifinished inner pack is moved, moreover, aboundary D between each curved guide surface 56 and each vertical guidesurface 60 in the discharge direction is alined with a folding line L ofthe upper side flap SF1. The respective extreme ends of the raked plates58 may be chamfered so as to have an arcuate profile in order to enablethe upper side flaps SF1 to be smoothly guided to the respective lowersurfaces of the raked plates 58 as the upper side flaps SF1 approach theraked plates 58.

FIG. 7 geometrically shows the curved guide surface 56 of each side flapfolding guide 48. The following is a geometrical description of aspecific shape of the curved guide surface 56.

First, an imaginary axis X-X′ is aligned with the folding line L of eachupper side flap SF1 as viewed in the moving direction of the cigarettebundle (semifinished inner pack), and a straight line A-B is definedextending from an arbitrary point A on the axis X-X′ to a point B in thedirection opposite to the moving direction, that is, at a given openingangle α (e.g., 45°) on the upper-stream side. Preferably, the openingangle α is an acute angle ranging from 10° to 80°, and can be freely setwithin this range. The straight line A-B is supposed to be contained ina plane that extends along the upper side flap SF1 that is not foldedyet.

Then, while the point A is moved in the moving direction of thecigarette bundle on the axis X-X′, the point B is rotated around theaxis X-X′ in the direction in which the upper side flap SF1 is folded.If the point of termination of the movement of the point A is A′, thepoint B rotates for a given angle β and reaches a point B′ while thepoint A moves in the interval A-A′. The angle β is adjusted to the samevalue as the folding angle (e.g., 90°) of the upper side flap SF1. If animaginary column around the axis X-X′ is C, as indicated by dashed linein the drawing, the point B moves on the outer peripheral surface of thecolumn C. Although the angle α between the straight line A-B and theaxis X-X′ undergoes no change in the example of FIG. 7, the angle α maybe changed in the middle. While the point A moves to the point A′,moreover, the ratio of the rotational angle of the point B to the moveddistance may be constant or variable in the middle.

Further, the distance between the points A and A′ is freely defined as afolding travel K for the upper side flap SF1. In FIG. 7, the side flapfolding guide 48 is shown exaggeratedly with respect to its longitudinaldirection. In the packaging machine of the present embodiment, however,the second wheel 10 and the third wheel 16 are located close to eachother, so that the overall length of the folding travel is restrictedstructurally.

If a curved surface is delineated in accordance with a moving trace ofline that covers the straight line A-B and the straight line A′-B′, afundamental shape of the curved guide surface 56 can be obtained. In thepresent embodiment, each side flap folding guide 48 is made of a memberhaving a square sectional shape, the actual shape of the curved guidesurface 56 involves the aforesaid curved surface.

FIG. 8 specifically shows a slope dS of an arbitrary infinitesimalportion of a curved surface around the axis X-X′, the curved surfacebeing obtained by the aforementioned geometrical method. The slope dS iscomposed of the opening angle α of the straight line A-B to the axisX-X′, a moving speed component dvX of the point A, and a peripheralspeed component dvR of the point B.

When the upper side flap SF1 passes through the aforesaid foldingoperation region K as the cigarette bundle is moved, the curved guidesurface 56 comes into surface contact with the upper side flap SF1. Inthis surface contact area, a folding surface pressure from each slope dSis applied to the upper side flap SF1. With respect to the movingdirection of the cigarette bundle, the slope dS has a downward gradientin the direction of the axis X-X′ or the direction of the folding line Lin accordance with the opening angle α of the straight line A-B, so thatthe folding surface pressure subjects the upper side flap SF1 to acentripetal force toward the folding line L. Thus, the movement of theupper side flap SF1 toward the folding line L can be efficientlyconverted into circular motion around the folding line L. Since thefolding surface pressure applies the centripetal force to the upper sideflap SF1, moreover, the upper side flap SF1 receives a force W in thedirection of rolling around the folding line L from the curved guidesurface 56 as the upper side flap SF1 moves (see FIGS. 7 and 8).

When the entire upper side flap SF1 passes through the folding travel K,folding the upper side flap SF1 is finished, whereupon the upper sideflap SF1 is lapped on the already folded portions. Further, the foldedportions and the upper side flap SF1 are sandwiched between the verticalguide surface 60 of the side flap folding guide 48 and the side face ofthe cigarette bundle.

According to the wrapper folding apparatus of the present embodiment, asdescribed above, the cigarette bundle can be discharged from the secondwheel 10, and the upper side flap SF1 can be folded in a short intervalof transportation for the delivery to the third wheel 16 in the nextstage. Since the upper side flap SF1 is efficiently subjected to thefolding surface pressure as the flap SF1 is guided along the curvedguide surface 56, moreover, it can be folding accurately.

FIG. 9 shows additional equipment for the curved guide surface 56 ofeach side flap folding guide 48. As shown in the drawing, a large numberof air jets 62 are formed in the curved guide surface 56. On the otherhand, a large number of air passages 64 are formed in the side flapfolding guide 48. One end of each air passage 64 communicate with itscorresponding air jet 62 on the curved guide surface 56. Further, theside flap folding guide 48 is formed having an air supply chamber 66that extends in the guide 48 from its end face opposite to the curvedguide surface 56. The air supply chamber 66 is supplied with compressedair from a pneumatic pressure source (not shown) by means of a nozzle68.

The compressed air that is fed into the air supply chamber 66 is ejectedfrom the air jets 62 through the air passages 64. The ejection of thecompressed air from the curved guide surface 56 can reduce thecoefficient of friction with the upper side flap SF1 and considerablylower its drag.

In the embodiment described above, the aluminized film is used as theinner wrapper for the cigarette bundle. However, the inner wrapper maybe metal foil, paper material, or some other film material.

The equipment for friction reduction shown as an example in FIG. 9ejects the compressed air from the curved guide surface 56. However,specific means may be modified according to the conditions of productsto be wrapped and wrappers used. For example, lubricating oil, water, orimpalpable powder may be supplied to the curved guide surface 56.

The specific shapes of the holding guides 38, side flap folding guides48, first and second lug folding guides 36 and 46, etc. may be suitablymodified according to the form of the packaging machine to which theyare to be arranged. It is to be understood that the other illustratedforms of the guides, pushers, etc. according to the present inventionare not particularly restricted, so that the forms of these members maybe variously modified in carrying out the invention.

1. A wrapper folding apparatus of a packaging machine, comprising: apackaging line along which a cigarette bundle is transported as thecigarette bundle is wrapped in an inner wrapper to form an inner pack,and in which an outer wrapper is folded around the inner pack to form apacked product of cigarettes; a folding turret having an inlet positionand an outlet position for the cigarette bundle in the middle of saidpackaging line and designed so that a pocket is supplied with thecigarette bundle and the inner wrapper in the inlet position in a mannersuch that the inner wrapper is folded around the periphery of thecigarette bundle; first lug folding guides provided for the pocket ofsaid folding turret and adapted to fold one-sided lug portions of theinner wrapper, formed by peripheral folding and located inside saidfolding turret with respect to the diametrical direction thereof, as theinner wrapper is peripherally folded, and to maintain the folded stateuntil the outlet position is reached; end-flap folding means for foldingend flaps of the inner wrapper to form the other-sided lug portionspaired with the one-sided lug portions on the inner wrapperrespectively, between the inlet and outlet positions of said foldingturret, and maintaining the folded state until the outlet position isreached; discharge means for discharging a semifinished inner pack,formed of the cigarette bundle partially wrapped in the inner wrapper,from the pocket in the outlet position of said folding turret; secondlug folding guides located in the outlet position and adapted to foldthe other-sided lug portions of the inner wrapper to form a pair of sideflaps respectively as the semifinished inner pack is discharged; sideflap folding guides located immediately on the lower-stream side of thesecond lug folding guides as viewed in the direction of discharge of thesemifinished inner pack and capable of folding one of the correspondingpair of side flaps after the other-sided lug portions are folded; atransportation turret located close to said folding turret; push meansfor pushing the discharged semifinished inner pack into a pocket of saidtransportation turret; and side flap folding edges provided for thepocket of said transportation turret and adapted to fold the other ofthe corresponding pair of side flaps as the semifinished inner pack ispushed in.
 2. The apparatus according to claim 1, wherein each of saidfirst lug folding guides includes a stationary guide, fixed in the inletposition of said folding turret and adapted to guide the one-sided lugportion in being folded as the inner wrapper is peripherally folded, anda holding guide adjoining the stationary guide in the direction ofsupply of the cigarette bundle in the inlet position and adapted to movetogether with the pocket as said folding turret rotates, thereby causingthe one-sided lug portion to hold the outer surface of the cigarettebundle.
 3. The apparatus according to claim 1, wherein each of said sideflap folding guides has a curved guide surface adapted to come intosurface contact with the one side flap when the side flaps passes as thesemifinished inner pack is discharged, so that the one side flap issubjected to a folding surface pressure in the direction of rollingaround a folding line of the one side flap in the surface contact area.4. A wrapper folding apparatus of a packaging machine, comprising: apackaging line along which a product to be packaged is transported witha wrapper subjected to peripheral folding and end-flap folding aroundthe product, whereby to-be-folded portions of the wrapper projectingsideways from the product are folded in succession; lug folding meansprovided in said packaging line and capable of folding lug portionspaired in the width direction of the product respectively, out of theto-be-folded portions of the wrapper, and holding the folded lugportions, thereby forming a pair of side flaps opposed to each other inthe thickness direction of the product respectively; transportationmeans for transporting the product along a folding line of the pair ofside flaps with the side flaps formed on the wrapper; side flap foldingguides adapted to guide the corresponding one of the side flaps in beingfolded as the product is transported; and curved guide surfaces formedon the side flap folding guides respectively and adapted to come intosurface contact with the one side flap during the passage of the sideflap, so that the one side flap is subjected to a folding surfacepressure in the direction of rolling around the folding line in thesurface contact area.
 5. The apparatus according to claim 4, whereineach of said curved guide surfaces includes a curved surface obtainedfrom a trace formed when a straight line, extending at an acute angle tothe folding line within a plane along the one side flap not folded yetand on the upper-stream side as viewed in the direction oftransportation of the product from the folding line, is rotated aroundthe folding line in a folding direction of the one side flap as thestraight line is moved in the direction of transportation.
 6. Theapparatus according to claim 5, wherein said straight line is rotatedfor an angle at which the one side flap is to be folded.
 7. Theapparatus according to claim 5, wherein the angle formed between thestraight line and the folding line is set within the range of 10° to80°.
 8. The apparatus according to claim 4, wherein each of said sideflap folding guides further has friction reducing means for lowering thecoefficient of friction between the curved guide surface and thewrapper.